Application extanded myoectomy in surgical treatment obstructive hypertrophic cardiomyopathy: immediate results

Background. Sudden cardiac death (SCD) has been recognized as one of the most devastating outcomes of hypertrophic cardiomyopathy (HCM). According to 2011 ACCF/AHA guidelines extended myomectomy, or myomectomy by Morrow, is the gold standard in treatment of patients with HOCM, however, the design of excision volume and mitral subvalvular apparatus (MSA) intervention is still unclear. Objective. The purpose of this study was to evaluate the design of excision volume during extended septal myectomy in patients with HOCM, as well as the safety and efficacy of this procedure. Methods. Between 2011 and 2013, 53 patients underwent extended myectomy procedures at our center. Mean age was 52.8±14.2 years (ranging from 22 to 74 years), with mean peak gradient reaching 89.9±27.2 mm Hg and thickness of the interventricular septum amounting to 25.8±4.1 mm. SAM syndrome was detected in all patients, with severe and moderate MR observed in 39 (73.5%) patients. The design of excision volume was based on MRI and TEE. To evaluate the results, use was made of TEE and direct tensiometry. Results. All procedures were performed with cardiopulmonary bypass (CPB) under mild (32° to 34°C) hypothermia. Mean CPB time was 119±40 minutes, cross clamping time was 88±34 minutes. In 52 (98.2%) cases radical extended myomectomy was performed on the basis of our excision volume design. In one (1.8%) case we had to additionally excise the mid area of the interventricular septum in order to obtain TEE and hemodynamic data. Postoperative SAM-syndrome was not observed in all cases. No early death was recorded. Peak LVOT gradient was 9.3±3.5 mm Hg (according to direct tensiometry) and 16.8±7.4 mmHg (according to TEE). Complete atrioventricular block was noted in 5 (9.4%) cases, in one (1.8%) case ventricular septal defect occurred. Conclusion. Our design of the excision volume for septal myectomy in patients with HOMC may be safely and effectively used for radical extended myomectomy.